July 30, 2015
Civitello et al. 2015
Frequency vs. density-dependent
Frequency-dependent (FD) vs. density-dependent (DD) vs.
Constant risk:
\(\dfrac{dI}{dt} = \beta S\)
Power law:
\(\dfrac{dI}{dt} = \beta S I^q\)
\(\dfrac{dI}{dt} = \beta S^p I^q\)
Negative binomial:
\(\dfrac{dI}{dt} = (kS) log(1 + \frac{\beta I}{k})\)
Theory
Little known beyond FD and DD transmission
Theory
Little known beyond FD and DD transmission
Data
Suggests support beyond FD and DD
(i.e. 'non-linear' transmission functions)
(Orlofske et al. in prep)
Effect of richness depends on interaction between competition and transmission
Strauss et al. 2015
watch for O'Reagan et al. in press AmNat
Multi-host, multi-parasite systems:
Most processes non-specific to parasites
Similar to habitat area-heterogeneity trade-off in free living species
Role of parasitism vs. mutualism
San Francisco Bay Area amphibian parasites
| -/- | -/0 | -/+ |
| 0/0 | 0/+ | |
| +/+ |
Local dynamics
Local dynamics \(\rightarrow\) regional dynamics
Local dynamics \(\neq\) regional dynamics if
(Chesson et al. 2005)
Most theory (but see Roche et al. 2012): short term
Most data: long-run